The army provided the financial support he needed to begin excavating when he arrived in Sumatra. To his disappointment there was nothing in the caves he searched which pointed to his desired bounty. Then he heard of a pair of skulls found in the Wajak Mountains in East Java. This redirected his search and after moving camp to Ngawi he unearthed his first significant find in 1891.

-The bones-
What Dubois found on the banks of the Solo River, 65 miles from where the Wajak Skulls had been discovered, was a skull cap and an upper molar. Many months later, in 1892, he unearthed a femur as well.

The skull cap had the large brow-ridge and a sloping forehead of an ape, however the size of the cap itself was much larger than that of any ape. The brain capacity for Java Man was calculated at 940cc. Dubois believed the femur and molar to be from Java Man as well, despite lacking the rest of the skeleton to piece it together with. Considering the large brain size and the femur's modern characteristics Dubois was certain he'd found the missing link, and he wanted everyone to know.

He wrote a number of papers, in journals published in both Europe and America, in which he introduced his find as belonging to Pithecanthropus erectus. He'd coined this classification around his belief that Java Man was an "upright walking ape-man," thanks to that one femur.

-The argument-
The scientific community was abuzz with controversy over this. In the early 1900s many people were unsure of Darwin and his crazy evolution claims. The world was still securely fastened in religion at that point, and claims like Dubois' were seen as threats against long held beliefs.

Creationists attacked Dubois, saying he was wrong and that what he had found was simply an ape skull. Under such immense preasure from the scientific community and religious orthodoxy he buckled. Dubois would no longer allow anyone to see the bones, and went so far as to rebury them under his own home where they remained for thirty years.

For a long time creationists argued that the reason Dubois had hidden his bones was because he no longer believed them to be human. Their claim was that he had changed his mind and now believed the skull belonged to a gibbon or a giant gibbon. This arguement stems from a quote taken from one of Dubois' articles in which he said,

Java Man was not a man, but a gigantic genus allied to the gibbons, however superior to the gibbons on account of its exceedingly large brain volume and distinguished at the same time by its faculty of assuming an erect attitude and gait.

As some people do when trying to win an argument, the creationists took a portion of the quote and put their own meaning behind it. Instead of the "He wasn't a man, he was a giant gibbon" that they argued he meant, Dubois was actually stating that Java Man was the link between men and gibbons. He was under the firm belief (although misguided) that man evolved from the gibbon.

As for the claims made by some that Java Man actually was a gibbon, you simply have to see the skull of each next to one another to understand the laughability of this. A gibbon skull (which has a brain capacity of about 100cc) could fit inside the skull of Java Man.

One of Dubois' long standing critics is a creationist by the name of Duane Gish who continued these arguments, and several other unfounded and unsupported claims, as late as 1995 despite the evidence.

-Modern science lends a hand-
Modern scientists have aided and debunked Dubois' claims about the bones he found. While it turned out he was correct, the skull cap did, in fact, belong to what was later renamed Homo erectus, it wasn't for the reasons he believed. The molar he had found turned out to belong to an orangutan, and the femur to modern man. In the end it was when Turkana Boy was discovered and the skulls of the two were compared that the similarities proved Java Man was indeed an "upright walking ape-man."